Internal combustion engines, including diesel engines, gasoline engines, gaseous fuel-powered, and other engines known in the art exhaust a complex mixture of air pollutants. The air pollutants may be composed of gaseous compounds, as well as solid particulate matter. Due to increased attention on the environment, exhaust emission standards have become more stringent, and the amount of gaseous compounds and particulate matter emitted to the atmosphere from an engine may be regulated depending on the type of engine, size of engine, and/or class of engine.
One method that has been implemented by engine manufacturers to comply with the regulation of air pollutants exhausted to the environment has been to remove these pollutants from the exhaust flow of an engine with filters. However, extended use and repeated regeneration of such filters may cause matter to build up in the filters, thereby reducing filter functionality and engine performance.
One method of removing matter from a filter may be to divert an exhaust flow from the clogged filter to a separate filter, without disconnecting either filter from the engine. While the exhaust flow is diverted, air may be directed through the clogged filter in a direction opposite the normal flow. Although functionally adequate, the second filter may increase the cost and size of the filter system. In addition, matter that is located out of the direct path of the reverse flow may be insufficiently removed from such systems.
U.S. Pat. No. 5,725,618 (the '618 patent) issued to Shimoda on Mar. 10, 1998, discloses an alternative system for removing particulate matter from an engine filter. In particular, the '618 patent discloses a particulate filter connected to an engine exhaust line and an impact air valve structure located within the exhaust line and downstream of the particulate filter. When the particulate filter is clogged with accumulated particulates, an impact wave is generated by instantly releasing air fed to a pressure accumulating chamber of the impact air valve. When the impact wave is transferred to a downstream face of the particulate filter in a reverse flow direction, it removes captured particulates from the filter. Following removal of the particulates from the filter, the particulates may be burned away upstream of the filter. In this manner, the '618 patent may remove particulate matter from an entire cross-section of the filter without the use of a secondary filter system.
Although the system of the '618 patent may improve the amount of particulate matter dislodged from a filter, the system requires an impact air valve in order to generate the reverse flow condition and the additional impact air valve increases the overall cost and size of the system. Furthermore, the system of the '618 patent may not provide an impact wave of optimal force and duration for removing particulate matter.
The present disclosure is directed to overcoming one or more of the problems set forth above.